The girl, who was 10 years old at the time of the incident, is accused of killing 3-month-old Brooklyn Foss-Greenaway in Fairfield on July 8, 2012.

Maine State Police said the suspect is the youngest person to be charged with manslaughter in the history of the state.

On Wednesday, prosecutors agreed to drop the felony charge and let the girl plead guilty to lesser misdemeanor charges.

"Because the juvenile code is really focused on rehabilitation, given the age of this child, it made no sense to think in terms of adult punishment. So the goal here was really to try to get her in a situation where she will receive the treatment she needs for an extended period of time," said deputy attorney general Bills Stokes.

Much of the court proceedings were closed to the public. Defense lawyers said the girl wasn't competent at the time of the incident and remains incompetent to stand trial.

"Think about yourself at age 12. What did you know about life? What did you know? She was 10 when this happened. Think about what life was like when you were in the fifth grade," said attorney Edwin Chester.

Nicole Greenaway, Brooklyn's mother, said she understands why prosecutors agreed to the plea deal, but she feels as though justice was not served.

"She's going to look at it as, 'I got away with murder,'" said Greenaway.

Greenaway wanted prosecutors to change the girl's mother, who was home when the incident occurred, but the state never brought any charges against the woman.

"It's really not a notion that is allowed under our criminal law, and so it would have been very problematic to do that," said Stokes.

THERE IS AN END TONIGHT TO THE CRIMINAL CASE AGAINST A 12-YEAR- OLD GIRL WHO POLICE SAY KILLED AN INFANT IN FAIRFIELD TWO YEARS AGO. THAT GIRL IS THE YOUNGEST PERSON IN áMAINE HISTORYá TO FACE A MANSLAUGHTER CHARGE. AND áEARLIER TODAYá.. THAT CHARGE WAS DROPPED. WMTW NEWS EIGHT'S PAUL MERRILL IS HERE NOW TO EXPLAIN WHAT HAPPENED. áááÑ THE DEFENDANT PLEADED GUILTY TO LESSER THE DEFENDANT PLEADED GUILTY TO LESSER MISDEMEANOR CHARGES. WE DON'T KNOW WHAT THOSE CHARGES ARE BECAUSE THAT JUVENILE COURT PROCEEDING WAS NOT OPEN TO THE PUBLIC. THE MOTHER OF THE THREE-MONTH- OLD VICTIM IN THIS CASE SAYS JUSTICE WAS NOT SERVED. "These are all of the people that she has touched their lives." NICOLE GREENAWAY CAME TO COURT TODAY WITH A POSTER COVERED IN PICTURES CHRONICLING THE SHORT LIFE OF HER DAUGHTER, BROOKLYN. "She was a happy baby. She always smiled. She was never really fussy. She slept all night since day one." IN JULY OF 2012, BROOKLYN FOSS- GREENAWAY WAS STAYING WITH FRIENDS AT THIS FAIRFIELD HOME WHEN PROSECUTORS SAY A TEN-YEAR-OLD GIRL KILLED HER. THAT GIRL, NOW TWELVE, WAS CHARGED WITH MANSLAUGHTER. TODAY, DEPUTY ATTORNEY GENERAL BILL STOKES AGREED TO DROP THAT FELONY CHARGE AND LET THE GIRL PLEAD GUILTY TO LESSER MISDEMEANOR CHARGES. "Because the juvenile code is really focused on rehabilitation, given the age of this child, it made no sense to think in terms of adult punishment, so the goal here was really to try to get her in a situation where she will receive the treatment she needs for an extended period of time." MUCH OF TODAY'S COURT PROCEEDINGS WERE CLOSED TO THE PUBLIC. DEFENSE LAWYERS SAY THE DEFENDANT WASN'T COMPETENT AT THE TIME OF THE INCIDENT AND REMAINS INCOMPETENT TO STAND TRIAL. "Think about yourself at age 12. What did you know about life? What did you know? She was ten when this happened. Think about what life was like when you were in the fifth grade." NICOLE GREENAWAY SAYS SHE UNDERSTANDS WHY PROSECUTORS AGREED TO THE PLEA DEAL BUT SHE FEELS AS THOUGH JUSTICE WAS NOT SERVED. "She's going to look at it as, 'I got away with murder.'" NICOLE WANTED PROSECUTORS TO CHARGE THE DEFENDANT'S MOTHER, WHO WAS HOME WHEN THE INCIDENT OCCURRED, BUT THE STATE NEVER BROUGHT ANY CHARGES AGAINST THAT WOMAN. "It's really not a notion that is allowed under our criminal law, and so it would have under our criminal law, and so it would have been very problematic to do that." (GFX) áááÑ THE DEFENDANT'S MOTHER LEFT COURT WITHOUT TALKING TO REPORTERS. THE DEFENDANT WILL RECEIVE TREATMENT AND COUNSELING INTO ADULTHOOD. NICOLE GREENAWAY SAY SHE'S HIRED A LAWYER TO PURSUE CIVIL CHARGES. LIVE IN THE STUDIO, PAUL

An Iranian military observation aircraft flew within 50 yards of an armed U.S. Navy helicopter over the Persian Gulf this month, sparking concern that top Iranian commanders might not be in full control of local forces, CNN has learned.